When hiking, is it harmful that I wear more layers of clothes and drink more water?

Question

I am a 38-year old that loves hiking as a hobby. I usually do 10-20km hikes with up to 2km altitude change. This year I started tours with a new crew and two people talked to me independently that my walking regime is unusual if not straightforward harmful. Basically, I feel the best if I'm warm and sweating. That means, I'll be more clothed and will drink more water than the most; but I'm not extreme - maybe one layer of clothes more than the next hiker. If anyone has its jacket zipped, it will be me. And a hat or hoodie - always. On a last hike (18km, 1km+,18°) hike, I drank cca 4.5 liters of water, with my urination somewhat less than usual. But these guys warned me about potential, but unspecified kidney (water) and heart (heat) problems. The probable reason for my routine is that I hate being cold or even cooled. The whole water thing is kinda necessary consequence of being warm.

So, do these guys have a point and should I push to adapt to lower temperature?

Answer 1

There are a couple of concerns to worry about, though neither is quite what your friends are saying:

First is electrolytes - depending on how much/what you eat you might end up short. Electrolyte tablets to add to some of your water might be a good idea. I'm the opposite to you and don't like to be too hot, but I use them in the summer; I've been known to drink (and mostly sweat out) 9 litres in a day cycling in the mountains. This is more likely to be an issue if you're going hiking on consecutive days, but one tablet in every other bottle will provide a bit of a top-up. The most important here is sodium (Na), i.e. common salt. If you like salty foods while hiking, they'll go a long way to meeting your needs.

Second - cooling off. If you feel the cold that much, you probably carry an extra layer, and that's a good idea. If you have an unplanned or longer-than-planned stop, sweaty clothes cool you down quickly (even with a windproof outer layer, though that helps). If an accident, navigational mishap, or other delay keeps you out as the temperature drops at the end of the day, that can get serious - so carry a bit of spare clothing.

Most people would try to minimise the amount of sweat in their clothes by adjusting their layers. You have more reason than some of us to choose good base and mid layers that have decent insulation while damp.

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To try to get to the bottom of where your friends are coming from, I assumed they were worried about you getting seriously dehydrated. It doesn't sound like you are - you're just doing extra work carrying more water. I might carry a similar weight in camera gear on a wildlife hike - the extra weight is your choice, no big deal. Dehydration does increase blood viscosity, and thicker blood is a risk for heart attacks. A lot has been written, not all trustworthy, so here's a link to a scientific paper on the subject. Similarly the kidneys are affected by dehydration, particularly chronic dehydration - another paper.

Again though, unless your risk is already elevated, and you're getting dehydrated, these aren't significant - I don't know (or want to know) if you're at high risk, and it doesn't sound like you're getting badly dehydrated. If this was a significant risk in general, people would be dropping like flies on every mountain in the summer, and we'd hear about it.

Answer 2

You're doing extremely physically challenging hikes, and whatever you're doing seems to be working for you. Ignore your friends and do what you like.

The only problem with bringing 4.5 liters of water is that it's a huge amount of weight. But if you feel thirsty for that much water, and it makes you happy, then presumably you've just consciously chosen to carry all that weight.

Drinking too much or too little water is not normally a big problem. There is a very wide range that's OK. There is a myth that "thirst is too late," or that you have to drink some huge amount of water every day in order to avoid becoming "dehydrated." This is nonsense. You will feel extremely thirsty long before you get anywhere near medical dehydration.

You're posting this on Nov. 30, which is northern hemisphere winter, and you describe wearing lots of layers because you don't want to get too cold. Furthermore, you're going up to high elevations in the mountains. So evidently you're in cold conditions, and this further reduces the danger of dehydration. I'll often do a long day hike in winter and only drink 500 ml of water.

It's true that drinking very large amounts of water in a short time can cause hyponatremia, which can be deadly and comes on without any sensation to give your brain a recognizable danger sign. The amount you're drinking, spread out over a long and strenuous day of hiking, is nowhere near that level.

Answer 3

Your co-hikers probably read or heard something somewhere about hyponatremia, without remembering the term or the concept. Four and a half liters is a lot so it might be a valid concern. Hydration is NOT a contest. Thirsty trumps dead every trip of the train.

Answer 4

The drinking isn't at a level I would regard as dangerous, but the overdressing is another matter.

Suppose you were injured--it need not be serious, just something that stops or greatly slows you. You're going to get quite cold, depending on the weather you could be in hypothermia territory. Sweating is ok if you can keep it up, it can go very badly if you can't.